suspect lower unit but dont know what it could be

christianneedle · Nov 2, 2011

I was running in choppy water. The motor would rev up and the boat would loose speed. If I were in a car, I would think that the transmission was slipping. Does anyone have any ideas as to what could cause this? Any ballpark price to repair?

Thanks.
Patrick

Monte1961 · Nov 2, 2011

Re: suspect lower unit but dont know what it could be

Check for wornout prop hub first!

boobie · Nov 2, 2011

Re: suspect lower unit but dont know what it could be

Agreed.

Tim Frank · Nov 2, 2011

Re: suspect lower unit but dont know what it could be

Not disagreeing that it could be the prop, but even easier (to diagnose, not to fix...

) would be if your engine's shaft length is "marginal" and the prop was actually cavitating on and off in the chop.

F_R · Nov 2, 2011

Re: suspect lower unit but dont know what it could be

Does it only do it in rough water? Probably cavitation (ventilation, for the purists). Either way, it is sucking air from the surface.

Does it happen in any kind of water? Slipping prop hub.

It isn't the lower unit, so relax.

boobie · Nov 2, 2011

Re: suspect lower unit but dont know what it could be

Us "Purists" like to use the correct terminology.

Tim Frank · Nov 2, 2011

Re: suspect lower unit but dont know what it could be

http://forums.iboats.com/showthread.php?t=517924

sschefer · Nov 2, 2011

Re: suspect lower unit but dont know what it could be

Could be something as simple as too much trim up. I have to laugh at myself because I did that last week totally by accident. I hit a patch of weeds at speed and when I was throttling it back to check it I must have been hitting the trim up switch. After I looked and saw it was clean I went to power back up and it kept overrevving at 2500 rpm so I just naturally figured I spun the hub. I pulled it out of the water and checked everything but couldn't find any problems so I took it back out and it was fine. The only thing it could have been was my dumb butt hitting the trim switch and not realizing it.

christianneedle · Nov 4, 2011

Re: suspect lower unit but dont know what it could be

Thanks soo much!! A prop hub is way better. Like this forum. Me thinks I'll learn a lot.

patrick

stylesabu · Nov 4, 2011

Re: suspect lower unit but dont know what it could be

you will, I still am

F_R · Nov 5, 2011

Re: suspect lower unit but dont know what it could be

boobie said:
Us "Purists" like to use the correct terminology.

I understand. But let's face it, the English language changes to accept commonly used words. We could get into what is an "engine" and what is a "motor" too. But Ole Evinrude called it a "motor", so motor it is.

Everybody calls air around the prop "cavitation", correcty or not. It's just a matter of where the air came from.

Then we could get into "electrloysis" and "galvanic corrosion" but we won't.

boobie · Nov 5, 2011

Re: suspect lower unit but dont know what it could be

I wonder if they called "cavitation" or "ventilation" back in 1909 ?? Wonder what Ole would have to say??

suspect lower unit but dont know what it could be

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